The present invention relates generally to particle blasting using cryogenic material, and is particularly directed to a method and device involving blasting with carbon dioxide pellets or particles that have been formed into a block from which carbon dioxide blast media is generated.
Carbon dioxide blasting systems are well known, and along with various associated component parts, are shown in U.S. Pat. Nos. 4,744,181, 4,843,770, 4,947,592, 5,018,667, 5,050,805, 5,071,289, 5,109,636, 5,188,151, 5,203,794, 5,249,426, 5,288,028, 5,301,509, 5,473,903, 5,520,572, 5,571,335, 5,660,580, 5,795,214, 6,024,304, 6,042,458, 6,346,035, 6,447,377, 6,695,679, 6,695,685, and 6,824,450, all of which are incorporated herein by reference.
Typically, particles, also known as blast media, are fed into a transport gas flow and are transported as entrained particles to a blast nozzle, from which the particles exit, being directed toward a workpiece or other target (also referred to herein as an article). Particles may be stored in a hopper or generated by the blasting system and directed to the feeder for introduction into the transport gas. One such feeder is disclosed in U.S. Pat. No. 6,726,549, issued on Apr. 27, 2004 for Feeder Assembly For Particle Blast System, which is incorporated herein by reference.
Carbon dioxide particles may be initially formed as individual particles, such as by extruding carbon dioxide through a die, or as a solid homogenous block. Within the dry ice blasting field, there are blaster systems that utilize pellets/particles and blaster systems which shave smaller blast particles from blocks of dry ice.
An apparatus for generating carbon dioxide granules from a block, referred to as a shaver, is disclosed in U.S. Pat. No. 5,520,572, which is incorporated herein by reference, in which a working edge, such as a knife edge, is urged against and moved across a block of carbon dioxide. These granules so generated are used as carbon dioxide blast media, being fed introduced into a flow of transport gas, such as by a feeder or by Venturi induction, by a feeder/air lock configuration, and thereafter propelled against any suitable target, such as a workpiece.
It is known to manufacture dry ice pellets/particles at a central location and ship them in suitably insulated containers to customers and work sites, whereas blocks of suitably sized dry ice are not readily available.
The present invention provides a device for forming pellets or large particles into blocks allowing the use of dry ice pellets or particles regardless whether a blasting system is configured for pellets/particles or granules. The resulting block is a non-homogenous agglomeration of pellets/particles formed into a block. Carbon dioxide blast particles may then be generated from the non-homogenous block, and propelled or otherwise directed toward a suitable target.
Although the present invention will be described herein in connection with a particle feeder for use with carbon dioxide blasting, it will be understood that the present invention is not limited in use or application to carbon dioxide blasting. The teachings of the present invention may be used in applications using any suitable type or size of particle blast media that can be reformed formed into blocks.
Reference will now be made in detail to an embodiment of the invention, an example of which is illustrated in the accompanying drawings.